From the Re-occupation of the Palace to the 1880's
Even long after it had been retaken from the Turks, Buda was not considered as a contender for the royal seat. During this time Buda castle's primary role was that of a fortification, and thus military functions determined its construction. The ruined curtain walls, which had been built in the Middle Ages, were quickly rebuilt and modernized. The southern Rondella, which was considered as the key strategic point of the palace and the entire castle quarter, was among the first sections to be repaired. After restoring the original walls it was made more defensible by surrounding it with modern bulwarks.
Besides the most necessary rubble clearance and demolition, the remnants of the palace that were still standing were left undisturbed. 
In the decade immediately after the re-occupation a massive military arsenal called in German the Zeughaus was built in the eastern half of the Northern Forecourt, within the palace area. Although the Zeughaus was burnt down in the 1723 fire, it was replaced in the period between 1725 and 1730. The new building constructed in the Baroque style remained a dominant element in Buda's view for 160 years.
The question of what to do with the remains of the medieval palace was raised in 1714 when the commander of the castle wanted to have everything pulled down. However, his idea was not put into practice and the new building was erected by using at least some of those parts of the old building that remained in better condition. The new "palace" was not designed for the monarch but rather for the commander and his staff. Consequently, its design was less refined: it was a two-storied building block raised on a quadrangular layout at the most southern part, with an enclosed courtyard and a narrow wing projecting from the western end of the northern side. The latter was redesigned from the former western wing of the Inner Court. In order to begin the construction work, the first step was to demolish the unnecessary ruins. This was the time when the greater part of the still standing medieval remnants was destroyed down to the rock surface, but usually not below.
Some of the medieval remains were used for the foundation. For example, in the cellar of the eastern wing of the new block (the King's Cellar), the solid ashlar built sustaining wall of the frontage of the former wing was integrated. Similarly to this, the new western wing was placed on top of the former Cisterna Regia (today: the Albrecht Cellar), though here buttresses and arches were used to strengthen the medieval construction.
The construction of the first Baroque Palace was never completed according to the original plans. However, its quadrangular block, albeit somewhat altered, still exists today and is known as building "E" in the palace-compound that stands today. Besides the medieval remains integrated in the new palace complex, a few other objects such as the Incomplete Tower, parts of the gatehouse at the western end of the 2nd Dry Moat, as well as the cellar from the south-eastern wing of Sigismund's Court used for powder-magazine, have also been preserved.
When in 1748 Antal Grassalkovich, president of the chamber managed to persuade Queen Maria Theresa to build a new royal palace, significant alterations were made to the old building and the entire area. Construction work began the following year. The second Baroque-style palace was designed on the basis of such plans, the new requirements of which demanded more space and higher expectations. Although the enclosed southern block as a starting point was preserved, its entire northern extension was pulled down. Thus the last existing palace wing built in the Middle Ages, as well as other remains that used to belong to the former courts, disappeared.
The new palace was erected with two other buildings that were placed north of the old building, and both of them had inner courts. Short, medial wings connected the old and new parts. The main façade of the symmetrically arranged building complex faced the Danube. Its ground plan looked like a flat or squared "C" or "U" letter. The royal residences and the throne hall, were located in the middle wing (today: building "D"). The three wings embraced a ceremonial court - cour d'honneur, - open towards the west which forms the eastern part of the Lion Courtyard today.
The construction work, which had begun at a vigorous pace, slowed down and was only finished by 1768-1769. The last stage was to consecrate the new Saint Sigismund-chapel built in the western wing of the northern block.
The queen only visited the palace, which was still under construction at the time, on two occasions, once in 1751 and again in 1764, and she only used it as her quarters during her second visit. Between 1766 and 1777, the palace was used as an occasional residence by the governor of Hungary, Prince Albert of Saxony and Teschen. In the meantime, the Order of Mary Ward's Nuns newly moved to Hungary was also accommodated here between 1770 and 1777. In 1771 Maria Theresa, after obtaining the precious hand-relic of King Saint Stephen from Raguza (today: Dubrovnik), sent this 'Holy Right' to Buda and entrusted the nuns with the preservation of it. A bit later she even ordered to erect a new chapel for it. The construction of the Holy Right Chapel, designed by Hillebrandt with an oval plan inside but octagonal planoutside, was completed by 1778. It was erected in the north-western corner of the northern wing, directly connected to the Saint Sigismund Chapel of the palace.
The translocation of another institution, i.e. the university of Nagyszombat (today: Trnava, Slovakia) to Buda, i.e. its temporary housing within the palace, resulted in a more serious external re-construction. This was because in addition to the alterations made inside the building complex, an observatory tower was also erected above the Danube-side façade of the main building, for use of the university that operated there between 1777 and 1784.
Based on a decision made by King Joseph II in 1784, the university was moved to Pest. The Military Headquarters that was moved from Pozsony, was also given home in the palace right until 1791, a move which reinstated the palace with some of the governing and administration roles it had enjoyed in the past. The symbolic significance of the palace was further increased by the king's decision, according to which the Holy Crown of Hungary was returned from Vienna and from this point kept more or less continually in the palace. For a long time the crown was placed in the rooms located above the entrance of the Saint Sigismund Church.
After this point - during the reign of King Leopold II - the palace again began to operate as a residence when Archduke Alexander Leopold of Habsburg, Palatine of Hungary moved into the palace. After his death in 1795 his younger brother Archduke Joseph succeeded him, first in the role of governor, then as the palatine of Hungary. - right until 1847. (During this time the royal family also visited the palace several times). From 1820 onwards, the undercroft area of the Saint Sigismud Church was used as a burial place and in 1830 it was re-structured and turned into a crypt based on the design of Franz Huppmann. Between 1827 and 1830 the observatory tower in the middle wing was dismantled and replaced by a third level. After his death in 1847, Archduke Joseph was succeeded by his son Archduke István (Stephen). The re-structuring of the Danube-side façade of the main wing, as well as the development of the new, large stable: the so-called Hofstallgebaude were initiated by him.
The 1848 -1849 revolution and war for independence, and the siege by the Hungarian Army in May 1849 affected the palace at this stage. Although the whole building was heavily damaged during the siege, particularly the middle and southern wings which burnt out, the restoration, re-construction and modernizing of the palace soon began. Emperor Franz Joseph used the palace as his occasional quarters as early as 1852, but it only properly re-gained its residential role in 1856 when the apartments of Archduke Albrecht of Habsburg, the governor of Hungary and his wife were established in the southern wing. The neo-rococo-style suite of the governor and his wife was located on the first floor, while on the second floor their two daughters lived with their retinue. Premises on the ground floor were related to their household. The middle building block remained as the quarters and ceremonial area for the monarch, but on special occasions the archduke also used the ceremonial hall with its pertinent premises. The archduke's chief marshal was accommodated in the northern wing. Albrecht lived in the palace until 1866 and after he left the southern wing was turned into a royal residence. Following this event, construction work on the palace was suspended for a while but throughout several visits the royal couple paid to the palace it became evident that the place was rather lacking for a stately court and that expansion would be required.
However, the following first construction work did not focus on expansion yet but put another expression of the royal splendor among the first considerations, which was only partially related to the palace building itself. In relation to the royal gardens, based on the design of Miklós Ybl, the Castle Bazaar with its neo-renaissance-style garden and architecture was established on the south-eastern slope of the Catsle Hill between 1875 and 1881.